A slim, medium-sized forktail, it is distinguished from similar species by its slate grey forehead, crown, and mantle.

The bird frequents the edges of fast-flowing streams and rivers, where it hunts small invertebrates by hopping among rocks or flying out over the water.

The slaty-backed forktail is found near streams and rivers in tropical and subtropical regions, occasionally straying further from flowing water to the edges of roads and trails.

Generally a solitary bird, it may occasionally be found in pairs, or in family groups in the breeding season.

The forktail is found in the central and eastern Himalayas, the Indian Sub-continent, southern China and continental Southeast Asia.

Its wide distribution and apparently stable population have led to it being classified as a species of least concern by the International Union for Conservation of Nature.

[4] The slaty-backed forktail is found near fast-flowing water bodies in tropical and sub-tropical montane broadleaf forests, as well as near cultivated areas.

[4] A 2000 paper studying birds in northwest India and Nepal found that the incidence of slaty-backed forktails decreased with altitude.

The study also found that the slaty-backed forktail had a preference for streams that were bordered by dense and complex vegetation, and had firm and stable banks of earth.

[4] The species is found in the central and eastern Himalayas, from the Indian state of Uttarakhand in the west to Myanmar in the East, including Nepal, and Bhutan.

It is also found in southern China, in southeast Tibet, and in the provinces of Sichuan, Yunnan, Guizhou, Fujian and Zhejiang, and possibly in Hainan.

Its range in South-East Asia includes Thailand, Vietnam, Laos, Cambodia, peninsular Malaysia, and Hong Kong.

It has been estimated as 300-1600m above sea level in northern India, 900–1675 in Nepal, 400–1800 in southern China and the adjacent areas of Thailand, above 500m in Cambodia, above 800m in Malaysia, and 800-2200m in Bhutan.

[7][3] Though it generally forages by hopping in an agile manner among rocks, it also makes brief forays above the water to snatch food items from the surface.

[4] In the South-East Asian parts of its range the bird is sedentary, while in the Himalayas it is observed to move over an elevational gradient.

[3] A 1998 study found that the species moved locally in response to rising water levels in the monsoon season.